This description relates to power semiconductor devices, and, more particularly, to power transistors and thyristors that include monolithically integrated or discrete transient voltage suppression.
Power semiconductor devices, including transistor and thyristors, are used in many power electronic systems. Some semiconductor devices, such as field effect transistors (FET) have a thin oxide layer at the gate which acts as a dielectric. When the terminals are exposed to transient overvoltages (due to EMI, voltage spikes, static discharge etc.), even for a very short duration, the one or more semiconductor layers in the device can rupture, potentially destroying the device. Similarly, devices such as thyristors, require a gate electrode for current injection, to facilitate latching. When this terminal is exposed to very large current levels, even for short durations, the device may suffer degradation which may include failure.
To protect these devices, bidirectional diodes are often coupled between the terminals. However, the diodes take up space on circuit boards or enclosures housing the semiconductor devices. Moreover, electrically coupling the devices together using wires or traces tends to increase the reactance of the connection and may slow the response of the transient voltage suppressor.